Liquid columns, such as water columns, are known. Liquid columns are used to determine the level of liquid in vessels (such as boilers, tanks, and drums). Liquid level indicators are also known. Liquid level indicators are connected to liquid columns and are used to display the level of liquid in vessels.
Liquid columns include probes. The probes are used to determine the level of liquid in the liquid column and, thus, the level of liquid in the vessel. Over time, the probes can become contaminated leading to inaccurate liquid level readings. In order to reduce contamination and, thus inaccurate liquid level readings, the probes should be periodically cleaned. Determining when to clean the probes can be difficult.